Variation in adherence to external beam radiotherapy quality measures among elderly men with localized prostate cancer

Abstract

Purpose: To characterize the variation in adherence to quality measures of external beam radiotherapy (EBRT) for localized prostate cancer and its relation to patient and provider characteristics in a population-based, representative sample of U.S. men.

Methods and materials: We evaluated EBRT quality measures proposed by a RAND expert panel of physicians among men aged >or=65 years diagnosed between 2000 and 2002 with localized prostate cancer and treated with primary EBRT using data from the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare program. We assessed the adherence to five EBRT quality measures that were amenable to analysis using SEER-Medicare data: (1) use of conformal RT planning; (2) use of high-energy (>10-MV) photons; (3) use of custom immobilization; (4) completion of two follow-up visits with a radiation oncologist in the year after therapy; and (5) radiation oncologist board certification.

Results: Of the 11,674 patients, 85% had received conformal RT planning, 75% had received high-energy photons, and 97% had received custom immobilization. One-third of patients had completed two follow-up visits with a radiation oncologist, although 91% had at least one visit with a urologist or radiation oncologist. Most patients (85%) had been treated by a board-certified radiation oncologist.

Conclusions: The overall high adherence to EBRT quality measures masked substantial variation in geography, socioeconomic status in the area of residence, and teaching affiliation of the RT facility. Future research should examine the reasons for the variations in these measures and whether the variation is associated with important clinical outcomes.

Figure 1

Definition of study cohort Text legend: * Includes cases from Greater California, Kentucky, Louisiana, and New Jersey registries starting in 2000. Note: Patients with inadequate Medicare records were excluded from the analysis. Medicare Part A and B coverage is required to ascertain treatment from Medicare records. Patients with health maintenance organization (HMO) coverage were also excluded because Medicare data does not include records for HMO enrollees.

Figure 2

Secular Trends in Adherence to Five Radiotherapy Quality Measures among 23,018 Medicare Beneficiaries with Localized Prostate Cancer, 1994 to 2002 Text legend: § We classified 1,257 patients whose immobilization was not reported as having received non-custom immobilization. ¶ We excluded 3% (789) of patients who could not be linked to their physician in the AMA Masterfile. † We classified 1,007 patients in 2001 and 2002 who received IMRT but whose photon energy was not reported as having received high energy photons. We classified 380 patients whose photon energy was not reported as having received photon energies ≤ 10 MV. †† Conformal radiotherapy includes 3D conformal and intensity modulated radiotherapy. We classified 217 patients whose treatment planning technique was not reported as having received non-conformal radiotherapy. *We excluded 1,731 patients in 2002 who had less than 12 months of follow-up for evaluation of claims following completion of radiotherapy. **Includes cases from Greater California, Kentucky, Louisiana, and New Jersey registries starting in 2000.